Question

If a chemical accepted \(\mathrm{H}^{+}\) from the surrounding solution, the chemical would be a(n) a. base. b. acid. c. buffer. d. Both a and c are correct.

Short answer

a. base.

Step-by-step solution

Recall the definition of acids and bases

Acids are substances that release \(\mathrm{H}^{+}\) ions (protons) when dissolved in water, while bases are substances that accept \(\mathrm{H}^{+}\) ions (protons).

Recall the definition of a buffer

A buffer solution is a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid. It is used to maintain a specific pH level by accepting or donating protons as necessary.

Identify the correct answer

Based on the information in Step 1, the chemical that accepts \(\mathrm{H}^{+}\) ions (protons) from the surrounding solution must be a base. Therefore, the correct answer is: a. base.

Key concepts

Acids

Let's dive into the basics of acids. At the simplest level, acids are substances that can donate protons, which are typically represented in the form of hydrogen ions (\( \mathrm{H}^{+} \)).
This characteristic allows acids to interact with bases in a chemical reaction.
Another common feature of acids is that they have a low pH level, usually below 7.

• Acids can be found in many everyday substances like vinegar, lemon juice, and even in your stomach.
• When acids dissolve in water, they release \( \mathrm{H}^{+} \) ions, increasing the concentration of these ions in the solution.
• Examples of strong acids include hydrochloric acid (\( \mathrm{HCl} \)) and sulfuric acid (\( \mathrm{H}_2\mathrm{SO}_4 \)).

Understanding the nature of acids helps us see how they can participate in reactions by donating \( \mathrm{H}^{+} \). It also helps explain why they typically have sour tastes and turn blue litmus paper red.

Bases

Bases are just as crucial in chemistry as acids, though they operate in a fundamentally different way. Instead of donating hydrogen ions, bases perform the opposite role.
They accept \( \mathrm{H}^{+} \) ions from their surroundings, which can typically neutralize acids when they come into contact.
The defining characteristic of bases is their ability to increase the hydroxide ion (\( \mathrm{OH}^{-} \)) concentration in a solution.

• Bases typically have a bitter taste and slippery feel, like the sensation of soap.
• They have a pH greater than 7, indicating a lower concentration of \( \mathrm{H}^{+} \) ions.
• Common examples include sodium hydroxide (\( \mathrm{NaOH} \)) and baking soda (\( \mathrm{NaHCO}_3 \)).

A deeper understanding of bases highlights their importance in balancing chemical reactions, especially in neutralizing acids to form water and salts. Recognizing the role of bases in these processes can help clarify how chemical equilibrium is achieved in reactions.

Buffer Solutions

Buffer solutions are special chemical systems designed to resist changes in pH levels. They are incredibly useful in both biology and chemistry.
Imagine a buffer as a dedicated team working to keep the pH steady when acids or bases are added to the mixture.

• A buffer usually consists of a solution containing a weak acid and its conjugate base, or a weak base and its conjugate acid.
• The weak acid and its conjugate base in a buffer work together by donating (\( \mathrm{H}^{+} \)) ions when the solution tends to become too basic, and by accepting \( \mathrm{H}^{+} \) ions when it tends to become too acidic.
• This ability to neutralize small quantities of additional acid or base helps maintain a stable pH, which is essential for many biological processes, such as enzyme function.

By using buffers, chemicals can maintain certain pH prerequisites for reactions. This resistance to pH changes is critical in many systems, including human physiology, where the pH of blood is tightly regulated.